1. Field of the Invention
The present invention relates to a seat for vehicle in which a seat back can be folded onto a seat cushion, and more particularly to a center-folding seat for vehicle in which the seat back can be tilted with respect to the seat cushion by means of a reclining mechanism comprising a base member secured to the seat cushion, and a rotating arm rotatably supported by the base member, and in which the seat back can be folded onto the seat cushion by means of a center-folding mechanism which comprises an arm plate, rotatably supported on the rotating end side of the above rotating arm and attached to each frame of both sides of the seat back.
Furthermore, the present invention relates to a seat for vehicle, in which a seat back including a child seat or an arm rest or the like therein can be tilted to a seat cushion, and more particularly to a seat for vehicle in which the seat back is attached to the seat cushion so as to be capable of being tilted by means of a reclining mechanism comprising a base member secured to the seat cushion, and a rotating arm rotatably supported by the base member, and in which the rotating arm is rotatably provided with a bracket to be connected to the child seat or the arm rest so that the child seat or the arm rest arm rest can be mounted within the seat back.
2. Description of the Related Art
FIG. 1 and FIG. 2 show a conventional center-folding seat for vehicle of this type which has been proposed. As shown in FIG. 1, according to this conventional seat, a center-folding seat 301 comprises a seat back 303 attached to a seat cushion 302, provided on the floor surface of the vehicle. A reclining mechanism 304, generally comprising a rotating arm 304b rotatably supported by a base member 304a, which is provided on the seat cushion 302 side, enables the seat back 303 to be reclined.
The center-folding seat 301 further comprises an arm plate 305 which is rotatably provided on the rotating end side of the rotating arm 304b. The seat back 303 is secured to this arm plate 305.
Therefore, the seat back 303 can be adjusted to a predetermined reclining angle by operating an operation lever 304c so as to cancel the lock between the base member 304a and the rotating arm 304b, whereby a built-in spring (not shown in the diagram) turns the rotating arm 304b in a counter-clockwise direction, as shown in FIG. 1. This causes the seat back 303 to collapse forward, however when the operation lever 304c is released at the predetermined reclining angle, the seat back 303 becomes fixed in that position.
Next, as shown in FIG. 2, in order to fold over (hereinafter "center-fold") the seat back 303, so as to enable the back face 303a of the seat back 303 to be used as a table, or alternatively, to enable more space to be freed within the vehicle in order to store luggage, the lock between the arm plate 305 and the rotating arm 304b is cancelled so that the arm plate 305 is rotated in a counter-clockwise direction with a rotate support point 305a as the base as shown in FIG. 1. Consequently, the seat back 303 is also folded over to the seat cushion 302 side, thereby becoming center-folded. The back face 303a of the seat back 303 can now be used as a table, or the space behind the center-folding seat 301 can be effectively used to store luggage.
However, when the seat back 303 of the conventional center-folding seat 301 is folded forward to the center-folded state and used as a table or for placing luggage thereabove, since the arm plate 305 is rotatably supported by the rotating arm 304b, the rotating arm 304b tilts at the rear (for instance, in a case when the seat back 303 has been center-folded to a deeply collapsed state), though it is desirable that the back face 303a of the seat back 303 maintains a horizontal position. Therefore, when the seat back 303 is center-folded, the back face 303a of the seat back 303 tilts at the rear end instead of keeping a horizontal position. This results in a disadvantage of inconvenience when the center-folded seat back 303 is to be used as a table or for placing luggage thereon.
Furthermore, when the seat back 303 is center-folded as shown in FIG. 2, the seat back 303 is supported only by the strength of the reclining mechanism 304. Therefore, there is a problem that, when a large load is applied on the center-folded seat back 303, shaking and the like are caused, leading to poor stability and inconvenience.
On the other hand, FIG. 3 shows a seat for vehicle comprising a reclining mechanism, a center-folding mechanism and a child seat, which is contained within the seat back. In the diagram, a center-folding seat 501 for vehicle comprises a seat back 503, capable of being tilted onto a seat cushion 502 by means of a reclining mechanism 504. The reclining mechanism 504 enables the seat back 503 to be folded over onto the upper face of the seat cushion 502. The seat back 503 contains a child seat 506 which is set in place by being collapsed forward.
And, as shown in FIG. 4, the above reclining mechanism 504 comprises a base member 504a, attached to the seat cushion 502, a rotating arm 504b, rotatably supported by the base member 504a, and an arm plate 505, constituting a center-folding mechanism, connected to the rotating arm 504b. In other words, the seat back 503 can be adjusted to a predetermined reclining angle by operating an operation lever 504c so as to cancel the lock between the base member 504a and the rotating arm 504b. Releasing the operation lever 504c, as a result, the basemember 504a and the rotating arm 504b becomes locked in that position, thereby locking the seat back 503 to the seat cushion 502 at the predetermined reclining angle.
Furthermore, when freeing more space or the like inside the vehicle, the seat back 503 can be collapsed Forward around a rotation center 505a of an arm plate 505, secured to both sides of the seat back 503, and stored over the upper face of the seat cushion 502.
However, it is a disadvantage of the conventional center-folding seat 501 that, since the child seat 506 can be pulled in or out irrespective of the reclining angle of the seat back 503, it is even possible to use the child seat 506, for instance, at an inappropriate reclining angle. The unsatisfactory seating position in such a case requires the set position of the child seat 506 to be corrected again, which is not preferable with respect to convenience.
And, as shown in FIG. 5, there is a further disadvantage that the lock of the reclining mechanism 504 may sometimes be inadvertently cancelled while the child seat 506 is being used, leaving room for improvement as regards safety and protection of the child seat 506. FIG. 6 shows a case envisaged in which the center-folding mechanism has been mistakenly activated while the child seat 506 is being used, allowing the seat back 503 to move. Consequently, the conventional center-folding seat 501 has a low level of comfort.
Furthermore, considering a seat type having a movable arm rest provided within the seat back 503 in addition to the child seat 506, it has been pointed about that there is a possibility of the arm rest being used at an unnatural reclining angle. Moreover, when the seat back 503 collapses forward due to the reclining mechanism 504 being unlocked while the arm rest is being used, or when the center-folding mechanism has been mistakenly operated, in a case where the seat back 503 has been folded over and stored, the arm rest will be damaged.
The problems described above also apply to a type of seat for vehicle in which the center-folding mechanism has been removed. In such a case, when the reclining mechanism 504 is unlocked while the child seat 506 is being used, the level of comfort is lowered.